diff --git a/README.md b/README.md
index 6be4b73..a63e61b 100644
--- a/README.md
+++ b/README.md
@@ -220,7 +220,6 @@ const defaultStyles = {
       addedGutterBackground: '#cdffd8',
       removedGutterBackground: '#ffdce0',
       gutterBackground: '#f7f7f7',
-      gutterBackgroundDark: '#f3f1f1',
       highlightBackground: '#fffbdd',
       highlightGutterBackground: '#fff5b1',
       codeFoldGutterBackground: '#dbedff',
@@ -246,7 +245,6 @@ const defaultStyles = {
       addedGutterBackground: '#034148',
       removedGutterBackground: '#632b30',
       gutterBackground: '#2c2f3a',
-      gutterBackgroundDark: '#262933',
       highlightBackground: '#2a3967',
       highlightGutterBackground: '#2d4077',
       codeFoldGutterBackground: '#21232b',